igii.] 



WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. 



385 



continuous set, interruption being necessary for only a few seconds 

 to change generators. There were consequently no appreciable 

 variations in temperature or pressure. 



The results as taken are plotted in the lower curves of Fig. 5 

 in which observations for ascending and descending values of fre- 

 quency are plotted as crosses and circles respectively. The irregular 

 shape of these curves repeated itself accurately in experiments over 



CvCufS PER SecON D 



Fig. 5. 



the same range of frequency with other wires. Since the trans- 

 former was operating over a wide range of frequency at approxi- 

 mately the same value of voltage, and its magnetizing current was 

 therefore variable, a variation of wave form due to the armature 

 reaction of the generator appeared probable. Oscillograms were 

 therefore taken of the voltage at the terminals of the low voltage 

 secondary coil at frequencies 20. 35, 55, 60, 65 and 91 cycles, and 

 at transformer excitation corresponding to 50 volts on the same coil. 

 The ratios of maximum to effective values of these waves were 



PROG. AMER. PHIL. SOC, L. 200 Y, PRINTED AUG. 5, I9II. 



